Method and system for pre-cooler exhaust energy recovery

Abstract

An energy recovery system and method of generating an auxiliary source of electrical power in a bleed air supply system are provided. The energy recovery system includes a compressor air supply precooler including a first flowpath configured to channel compressor bleed air between a precooler inlet and a precooler outlet. The precooler further includes a second flow path configured to channel a coolant between a precooler coolant inlet and a precooler coolant outlet. The precooler is configured to cool compressor bleed air from a bleed air source. The system also includes a thermoelectric generator coupled in flow communication with the precooler coolant outlet.

What is claimed is: 
     
         1 . A gas turbine engine energy recovery system comprising:
 a compressor air supply precooler comprising a first flowpath configured to channel compressor bleed air between a precooler inlet and a precooler outlet, said precooler further comprising a second flow path configured to channel a coolant between a precooler coolant inlet and a precooler coolant outlet, said precooler configured to cool compressor bleed air from a bleed air source; and   a thermoelectric generator coupled in flow communication with said precooler coolant outlet.   
     
     
         2 . The system of  claim 1 , wherein said thermoelectric generator comprises an inlet configured to receive a flow of heated air from said precooler coolant outlet. 
     
     
         3 . The system of  claim 1 , wherein said precooler outlet is coupled in flow communication with an environmental control system (ECS). 
     
     
         4 . The system of  claim 1 , wherein said precooler comprises an air-to-air heat exchanger in fluid communication with a source of cooling air. 
     
     
         5 . The system of  claim 4 , wherein said source of cooling air comprises a portion of fan air. 
     
     
         6 . The system of  claim 1 , wherein said bleed air source comprises a low pressure bleed air port positioned between a first and a last stage of said compressor and a high pressure bleed air port positioned between said low pressure bleed air port and said last stage of the compressor. 
     
     
         7 . The system of  claim 1 , wherein said bleed air source is selectable between the low pressure bleed air port and a high pressure bleed air port. 
     
     
         8 . The system of  claim 1 , wherein said thermoelectric generator comprises a thermoelectric module comprising a first surface and an opposing second surface, said thermoelectric module configured to generate a current flow of electricity according to a Seebeck effect when a thermal gradient is maintained across first surface and said second surface. 
     
     
         9 . The system of  claim 1 , wherein said thermoelectric generator comprises a thermoelectric module comprising a first surface coupled in flow communication with said precooler coolant outlet and an opposing second surface coupled in flow communication with a flow of relatively cool cooling fluid. 
     
     
         10 . The system of  claim 1 , wherein said thermoelectric generator comprises a plurality of thermoelectric modules positioned adjacently with respect to each other in a stack of thermoelectric modules, said thermoelectric modules spaced to provide a flow passage between adjacent thermoelectric modules of said plurality of thermoelectric modules. 
     
     
         11 . The system of  claim 1 , wherein said thermoelectric generator comprises at least one of bismuth telluride (Bi 2 Te 3 ), lead telluride (PbTe), and silicon germanium (SiGe). 
     
     
         12 . The system of  claim 1 , wherein said thermoelectric generator comprises nanoscale features comprising at least one of nanoparticles, nanowires, and nanointerfaces formed in bulk semiconductor materials. 
     
     
         13 . A method of generating an auxiliary source of electrical power, said method comprising:
 channeling a portion of an aircraft engine fan air flow to a heat exchanger;   cooling a flow of bleed air using the portion of aircraft engine fan air flow in the heat exchanger; and   generating electrical energy in a thermoelectric generator coupled in flow communication with the heat exchanger.   
     
     
         14 . The method of  claim 13 , wherein generating electrical energy in a thermoelectric generator comprises generating electrical energy in a thermoelectric generator comprising at least one of bismuth telluride (Bi 2 Te 3 ), lead telluride (PbTe), and silicon germanium (SiGe). 
     
     
         15 . The method of  claim 13 , wherein generating electrical energy in a thermoelectric generator comprises generating electrical energy in a thermoelectric generator comprising at least one of nanoparticles, nanowires, and nanointerfaces formed in bulk semiconductor materials. 
     
     
         16 . The method of  claim 13 , wherein generating electrical energy in a thermoelectric generator comprises generating electrical energy in a thermoelectric generator comprising Ag 1-x Pb m SbTe 2+m . 
     
     
         17 . A turbofan engine comprising:
 a core engine including a multistage compressor;   a fan powered by a power turbine driven by gas generated in said core engine;   a fan bypass duct at least partially surrounding said core engine and said fan; and   a gas turbine engine energy recovery system comprising:
 a compressor air supply precooler comprising a first flowpath configured to channel compressor bleed air between a precooler inlet and a precooler outlet, said precooler further comprising a second flow path configured to channel a coolant between a precooler coolant inlet and a precooler coolant outlet, said precooler configured to cool compressor bleed air from a bleed air source; and 
 a thermoelectric generator coupled in flow communication with said precooler coolant outlet. 
   
     
     
         18 . The engine of  claim 17 , wherein said thermoelectric generator comprises an inlet configured to receive a flow of heated air from said precooler coolant outlet. 
     
     
         19 . The engine of  claim 17 , wherein said thermoelectric generator comprises a thermoelectric module comprising a first surface and an opposing second surface, said thermoelectric module configured to generate a current flow of electricity according to a Seebeck effect when a thermal gradient is maintained across first surface and said second surface. 
     
     
         20 . The engine of  claim 17 , wherein said thermoelectric generator comprises at least one of bismuth telluride (Bi 2 Te 3 ), lead telluride (PbTe), and silicon germanium (SiGe). 
     
     
         21 . The engine of  claim 17 , wherein said thermoelectric generator comprises nanoscale features comprising at least one of nanoparticles, nanowires, and nanointerfaces formed in bulk semiconductor materials.